org.springframework.jdbc.core.ColumnMapRowMapper Maven / Gradle / Ivy
/*
* Copyright 2002-2021 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.jdbc.core;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.util.Map;
import org.springframework.jdbc.support.JdbcUtils;
import org.springframework.lang.Nullable;
import org.springframework.util.LinkedCaseInsensitiveMap;
/**
* {@link RowMapper} implementation that creates a {@code java.util.Map}
* for each row, representing all columns as key-value pairs: one
* entry for each column, with the column name as key.
*
* The Map implementation to use and the key to use for each column
* in the column Map can be customized by overriding {@link #createColumnMap}
* and {@link #getColumnKey}, respectively.
*
*
Note: By default, {@code ColumnMapRowMapper} will try to build a linked Map
* with case-insensitive keys, to preserve column order as well as allow any
* casing to be used for column names.
*
* @author Juergen Hoeller
* @since 1.2
* @see JdbcTemplate#queryForList(String)
* @see JdbcTemplate#queryForMap(String)
*/
public class ColumnMapRowMapper implements RowMapper> {
@Override
public Map mapRow(ResultSet rs, int rowNum) throws SQLException {
ResultSetMetaData rsmd = rs.getMetaData();
int columnCount = rsmd.getColumnCount();
Map mapOfColumnValues = createColumnMap(columnCount);
for (int i = 1; i <= columnCount; i++) {
String column = JdbcUtils.lookupColumnName(rsmd, i);
mapOfColumnValues.putIfAbsent(getColumnKey(column), getColumnValue(rs, i));
}
return mapOfColumnValues;
}
/**
* Create a Map instance to be used as column map.
* By default, a linked case-insensitive Map will be created.
* @param columnCount the column count, to be used as initial
* capacity for the Map
* @return the new Map instance
* @see org.springframework.util.LinkedCaseInsensitiveMap
*/
protected Map createColumnMap(int columnCount) {
return new LinkedCaseInsensitiveMap<>(columnCount);
}
/**
* Determine the key to use for the given column in the column Map.
* By default, the supplied column name will be returned unmodified.
* @param columnName the column name as returned by the ResultSet
* @return the column key to use
* @see java.sql.ResultSetMetaData#getColumnName
*/
protected String getColumnKey(String columnName) {
return columnName;
}
/**
* Retrieve a JDBC object value for the specified column.
*
The default implementation uses the {@code getObject} method.
* Additionally, this implementation includes a "hack" to get around Oracle
* returning a non standard object for their TIMESTAMP data type.
* @param rs the ResultSet holding the data
* @param index the column index
* @return the Object returned
* @see org.springframework.jdbc.support.JdbcUtils#getResultSetValue
*/
@Nullable
protected Object getColumnValue(ResultSet rs, int index) throws SQLException {
return JdbcUtils.getResultSetValue(rs, index);
}
}